1. Field of the Invention
The present invention relates to a rocking seat control apparatus, for example, an automatic rocking apparatus for use as an infant chair or bed, or stroller.
2. Description of the Prior Art
The continuing of a seat to sway automatically has been brought to realization in a chair equipped with rocking function as disclosed in JP P H11-89681 A. In the chair described in JP P H11-89681 A, a member composed of magnetic material is attached to a moveable seat supported on the chair. The magnetic member is bi-directionally attracted repetitively towards a solenoid when the latter is periodically energized and magnetized to cause the seat to sway. In the absence of continued attraction by the solenoid, the rocking amplitude of the seat will attenuate and the seat will eventually cease rocking. However, the presence of continued attraction by the solenoid allows the seat to continue to rock.
Also, to vary the amplitude of rocking of the seat controllably, the time duration in which the solenoid is repetitively magnetized can be rendered so that a selected time duration of repetitive magnetization of the solenoid may establish a preselected amplitude of the rocking of the seat.
The variability of the load imposed on the seat with time, however, prevents the amplitude of the rocking of the seat from being kept constant when the solenoid is repetitively magnetized at a selected value in the predetermined time. Also, the prior art has such a drawback that controlling the amplitude of the rocking of the seat preferably entails sensing the instantaneous current position and direction of movement of the seat, which has made it essential to include a large number of sensors in the control apparatus.
The first object of the present invention is accordingly to provide a rocking seat control apparatus that permits a seat to sway and to be rocked at a selected fixed amplitude without regard to the load variation imposed on the seat and that renders the rocking amplitude of the seat readily controllable while sensing an instantaneous current position and a direction of movement of the seat with a reduced number of sensors.
While an automatic rocking chair is thus provided that assures that the chair continues to rock with a fixed amplitude once established by a corresponding preset time duration of the repetitive magnetization of the solenoid, the constancy in amplitude of the rocking over time may make the rocking motion of the seat monotonous. It was shown that when infants seated on monotonously rocking chairs there were wide variations in their reactions.
Accordingly, it is the second object of the present invention to provide a rocking seat control apparatus whereby a seat occupant (infant) may uniformly experience a pleasant feeling and be comforted by imparting a moderate fluctuation to the rocking of the seat.
In order to attain the first object mentioned above, there is provided in accordance with the present invention in a first aspect thereof a rocking seat control apparatus, which comprises: a supported moveable seat having a magnetic member attached thereto; a solenoid means for bi-directionally attracting the said magnetic member repetitively to cause the seat to move in a positive and a negative direction alternately and thereby creating a rocking motion; an amplitude measuring means for measuring an amplitude of the seat being rocked and the rocking motion of the seat; an amplitude damping factor measuring means responsive to displacements in the positive and negative directions of the seat being rocked for measuring the extent of damping of the said amplitude caused while the seat is being rocked; and a solenoid energizing means for energizing the said solenoid means for a time period in which the seat is being rocked during traveling a distance that is the product of the said measured rocking motion and the said measured amplitude of damping factor.
The rocking seat control apparatus constructed as mentioned above, which can be controlled during a time period for which the solenoid means is energized to be controlled by a distance that is a product of the measured rocking motion and the measured amplitude damping factor, is designed to apply an impulse to the seat that compensates for an extent of damping of the rocking amplitude caused while the seat is being rocked, thereby permitting the rocking amplitude of the seat to be kept constant.
In the rocking seat control apparatus mentioned above, the said magnetic member may be comprised of a pair of magnetic sub-members attached to the seat and whose mid point is positioned to be displaced at a predetermined distance apart from the mid point of the said solenoid means.
This arrangement balances the magnetic force between the solenoid means and two magnetic members attached to the seat, where their mid point is positioned to be displaced at the predetermined distance apart from the mid point of the solenoid means by, and enables to rock the seat with a heavy load imposed thereon.
The rocking seat control apparatus mentioned above may further comprises the first light emitter disposed below a path of the seat being rocked; the second light emitter united to the said first light emitter; the first light reflector including a plurality of light reflector plates attached to the seat arranged in a row and spaced apart from one another across a predetermined spacing in the first direction in which the seat is rocked for reflecting light emitted from the said first light emitter; the second light reflector including a plurality of light reflector plates attached to the seat arranged in a row and spaced apart from one another across a predetermined spacing in a second direction parallel to the said first direction for reflecting light emitted from the said second light emitter, the said light reflector plates of the second light reflector being deviated in position from the said light reflector plates of the first light reflector by half the width of each of the said light reflector plates of the first light reflector; the first light receiver mounted united to the said first light emitter for receiving light reflected back from the said first light reflector; the second light receiver mounted united to the said second light emitter for receiving light reflected back from the said second light reflector; a change of rocking direction detecting means responsive to a light receiving pattern of the said first and second light receivers for detecting a turnabout of the seat being rocked; and a seat amplitude measuring means responsive to numbers of light reception signals issued from the said first and second light receivers for measuring an amplitude of the seat.
This arrangement, which requires that the light reflector plates of the first light reflector are deviated in position from the light reflector plates of the second light reflector by half the width of each of the light reflector plates of the first light reflector, allows the rocking amplitude of the seat to be measured in units each of which is as small as half the width of each of the reflector plates of the first reflector. Furthermore, a difference in the light receiving pattern on the time base between the first and second rows of the reflector plates is advantageously used to allow a turnabout of the rocking to be detected in response to the light receiving patterns of the first and second reflectors. Moreover, the arrangement enables the rocking amplitude of the seat to be measured precisely and instantaneously in response to a number of light receiving signals. Thus, it becomes possible to control the rocking amplitude with a minimum number of sensors.
In the rocking seat control apparatus mentioned above, it is advantageous that if the said light reflector plates of first light reflector and those of second light reflector are made equally in width and spacing to each other, the spacing which successive light reflector plates of each of the said first and second light reflectors are spaced apart is equal to the width of each of the reflector plates of the said first and second light reflectors.
In order to achieve the second object mentioned above, the present invention also provides a rocking seat control apparatus, which comprises: a moveable seat supported and having a magnetic member attached thereto; a solenoid means energizable to bi-directionally attract the said magnetic member repetitively, thereby rocking the seat; a drive circuit to control the magnetization of the said solenoid means; and a 1/f spectrum fluctuation computing circuit adapted to compute a target value corresponding to a target rocking motion of the seat being rocked in a mode of 1/f-type spectrum fluctuation and to enter the said target value into the said drive circuit.
This arrangement, which requires the drive circuit to control the solenoid means so as to give rise to a 1/f-type spectrum fluctuating rocking motion issued from a 1/f-type spectrum fluctuation computing circuit, makes the seat rock in a mode of a 1/f-type spectrum fluctuation. As a result, the seat occupant will experience a pleasant feeling and be comforted according to a 1/f-type spectrum fluctuation.
In the rocking seat control apparatus mentioned above, the said 1/f-type spectrum fluctuation computing circuit preferably includes an initial value input means adapted to be entered with the initial values of the said 1/f-type spectrum fluctuation.
This arrangement, which requires the initial values of a 1/f-type spectrum fluctuation to be preset at the initial value input means, permits attaining any fluctuating rocking motion as desired by appropriately presetting the initial values of the 1/f-type spectrum fluctuation.
The rocking seat control apparatus mentioned above, preferably further includes a target rocking motion input means for entering a target value corresponding to a given target rocking motion into the drive circuit of the said solenoid; and a switching means for selectively connecting either one of the said 1/f-type spectrum fluctuation computing circuits and the said target rocking motion input means to the said drive circuit.
This arrangement, which requires a switching means to be provided for selectively connecting either one of the 1/f-type spectrum fluctuation computing circuits and the target rocking motion input means to the said drive circuit of the said solenoid, enables either a seat rocking mode by the 1/f-type spectrum fluctuation computing circuit or a constant amplitude or swing seat rocking mode by the target rocking motion input means to be selectively established as desired.